The 37-year-old, of North Canterbury, has been running for 19 days now and does not plan to stop yet.
She is attempting to run the length of the country in 21 days, covering 100km each day.
Timmis said she was "in a lot of pain" after her 14-hour run from Maheno to Dunedin yesterday, but she was still in high spirits.
Runners from small towns along the way joined her for stretches of the trip, cheering her on and providing support.
She set off from Cape Reinga on December 18 and hoped to reach Bluff on January 8.
The current record stands at 35 days and 27 minutes, a fortnight longer than her schedule.
Taking on that much exercise was taking its toll and would have long-lasting effects, she said.
She had lost significant muscle mass and weight, and her appetite had been affected.
"I am very, very injured."
In 2011 she ran the length of Africa and in 2014 ran South Africa, however took those challenges at half the pace of her New Zealand run.
In 2017 she unofficially broke a world record after cycling across Australia in 74 days.
Timmis said she planned to raise $21,000 each for two separate charities during the 2100km trek. The money would go to Youthline and Young Minds, which was based in the UK.
She had raised more than $10,000 so far.
She was inspired to support youth mental health charities after she suffered a leg injury four years ago.
She had planned to take the challenge back then, but was instead left unable to run and with deteriorating mental health.
She got through it with the help of a good support network, which made her realise how much help some people needed.
"I’m a full-grown adult with a support network around me and I still found that really tough."
Going through that as a young person without that support must be "horrendous", she said.
She would be off from Dunedin at 4am today on her way to Kuriwao.
With only days left in her mission, she was planning on resting for "a very long time" once she hit the finish line.
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Comments
I must say that she has a lot of determination and is doing it for a good cause ... albeit for one overseas charity.
What I'm asking myself is, if she's pushing herself that hard that it will have as she puts it "long term effects" ... what are they going to be ... arthritis would probably be one obvious one, but what concerns me is the final cost to to her, her support network, and the people of NZ if she requires ongoing medical treatments.
She seems like a very intelligent lady, but there are less "taxing" ways to raise money than destroy your own body and possibly cost yourself and others a far greater amount both physically, mentally and financially, in the long term.
Doesn't seem a to be a logical way of going about it.
Can't people be sponsored for doing something that is both harmless to themselves and useful to society, such as being a blood donor, cleaning invasive species out of a patch of bush and keeping it clear for a year? It seems extraordinarily pointless to harm one's own body - or is pain with likely long-lasting damage what donors want, is it what motivates them to give? Is this what they pay for: "I am very, very injured."
I have read of people raising large sums for getting a tattoo advertising a big company. From the photo she has 4 unmarked limbs at present.